Remote control circuits for hydraulic motors

ABSTRACT

A simplified remote control system for a plurality of hydraulic motors in which the transmitter and receiver controllers are simplified by providing for only a single proportional control member at each location with on-off type controls for all of the motors and in which the hydraulic circuit incorporates a proportional valve in series with a plurality of on-off valves or bidirectional valves in direct control of the motors and in parallel circuit to proportionally control flow from a hydraulic source to all of the bidirectional controllers or valves simultaneously. This will permit speed and directional control with speed of operation being effected for all motors operated simultaneously and at the same rate.

United States Patent [191 Wilson [451 May 7, 1974 REMOTE CONTROL CIRCUITS FOR HYDRAULIC MOTORS [75] inventor: Wendell E. Wilson, Bloomington,

Minn.

[73] Assignee: Tel-E-Lect, Inc., Minneapolis, Minn.

[22] Filed: Oct. 16, 1972 [21] Appl. No.: 297,785

[52] US. Cl 182/148, 182/2, 343/225 [51] lnt Cl. B66f 11/04, B66c 23/62 [58] Field of Search 182/2, 141, 148; 212/8 R, 212/35 R, 35 HC; 340/171 PF, 171 R;

Knutson 3,774,217 11/1973 Bonner 343/225 Primary Examiner-Reinaldo P. Machado Attorney, Agent, or Firm-Schroeder Siegfried Ryan & Vidas 5 7] ABSTRACT A simplified remote control system for a plurality of hydraulic motors in which the transmitter and receiver controllers are simplified by providing for only a single proportional control member at each location with onoff type controls for all of the motors and in which the hydraulic circuit incorporates a proportional valve in series with a plurality of on-off valves or bidirectional valves in direct control of the motors and in parallel circuit to proportionally control flow from a hydraulic source toall of the bidirectional controllers or valves simultaneously. This will permit speed and directional control with speed of operation being effected for all motors operated simultaneously and at the same rate.

12 Claims, 4 Drawing Figures PATENTEDm 1 1974 SHEEI 2 BF 2 W QNB REMOTE CONTROL CIRCUITS FOR HYDRAULIC MOTORS My invention relates to remote control circuits of a plurality of motors and more particularly -to an improved radio control type circuit for the control of a plurality of motors of the hydraulic type utilizing a simplified transmitter and receiver circuit and an improved simplified hydraulic circuit for the use of a single proportional valve and a plurality of on-off valves to proportionally control speed of the motors from the transmitter with a simplified network in the transmitter and receiver. R

i In the past remote control circuits for motors and in particular for a plurality of motors have required proportional as well as on-off control at the transmitting and receiving point to effectively control the speed as well as direction of operation of the motors connected to the receiver. This structure becomes more complex when the connection between the transmitter and receiver is connectionless or in particular of the radio type. Radio controllers have'been used in remote control command posts in the control of motors and in particular in connection with cranes and mobile aerial towers in the past. Such circuits have required complexity in both transmitter and receiver as well as in the power circuits for the motors to operate the motors bidirectionally or unidirectionally with a desired speed of control. In the co-pending application of Robert Bonner and John Wiehe, Ser. No. 249,382, filing date May 1, 1972 and now US. Pat. No. 3,774,217, entitled RADIO CONTROL SYSTEM FOR MOBILE AE- RIAL PLATFORMS, apparatus of this type is disclosed utilizing radio control between a transmitter and receiver for effectively controlling a plurality of motors operating a mobile aerial tower. The transmitter and receiver require separate channels for each of the motors and complex electronic logic circuits to effect proportional as well as directional control of each motor.

The present invention is directed to a simplified control apparatus of this type in which the transmitter and receiver apparatus are simplified through the use of a plurality of on-off channels and a single proportional channel thereby simplifying the logic and transmitting and receiving portions of the control apparatus. In the Another object is to provide in a circuit of this type an improved simplified radio control circuit for controlling a plurality of hydraulic motors.

A still further object is to provide in a circuit of this type a simplified hydraulic power and control circuit with proportional and directional control for a plurality of motors.

Still another object of this invention is to provide an apparatus of this type which is low in cost and easy to maintain.

. These and other objects of this invention will become apparent from a reading of the attached description to.- gether with the drawings wherein.

FIG. 1 is a perspective view of a mobile aerial tower employing the invention;

FIG. 2 is a perspective view of a transmitter forthe improved circuit; 1 7

FIG. 3 is a perspective view of a receiver for the improved circuit; and

FIG. 4 is'a schematic view of the electric hydraulic V control circuit employed in the control of the plurality of motors for the mobile aerial tower of FIG. 1.

My invention in a remote control-system for a plurality of motors is shown in the drawings in connection withan-articulated scaffold or mobile aerial tower as one type of a structure employing a plurality of motors adapted to be controlled from a remote location. It'is further shown herein in connection with a radio type control in which the transmitter may be a portable unit adapted to be moved to varying locations for control ling at the receiving location a control system in the operation of the motors. Thus in FIG. 1, themobile aerial tower is indicated generally at 10. It is shown as being mounted on a mobile chassis or truck body, shown in part at 11. The chassis or truck structure. will includea power plant source adapted to provide a source of hydraulic fluid under pressure for the hydraulic motors, to be later identified, incorporated on the hydraulic or power circuit at the receiver controlling the operation of a plurality of motors, the power source or hydraulic source is connected through the proportional control valve in series with all of the directional control valves for each of the motors in a parallel relationship so that selectively one or all of the motors may be simultaneously operated under the direction of the proportional control valve and in accord with the proportional control commands from the transmitter. This improved circuit greatly simplifies the electronic and hydraulic portion of the circuit reducing the cost and maintenance of the same.

It is therefore the principal object of this invention to provide an improved remote control circuit for the operation of a plurality of hydraulic motors. V

Another object of this invention is to provide an improved radio type control system adopted to operate a plurality of motors associated with an articulated scaffold for the purpose of controlling the operation of the same.

articulated structure. In addition, the truck will provide a suitable power source of the electrical type for the components of the control system operating the hydraulic control valves. The articulated scaffold includes a base structure or platform 11 carried by the chassis which mounts a turntable type support indicated at 14, the latter being adapted to be oriented about a vertical axis in azimuth through 360 for the purpose of orienting the tower connected thereto in azimuth. A motor indicated at 13 of the hydraulic type is suitably connected to the turntable support for powering the turntable and rotating the same continuously and bidirectionally. The scaffold further includes a main boom element, indicated generally at 60, which may include one or more telescopically operated boom elements, such as is indicated. at 20, which is slidably mounted in the main boom element 16. The main boom element in turn is pivotally mounted on the turntable type support 14 through a pivot structure 15 and a suitable hydraulic motor of the linear type, indicated. at 18, is coupled between the turntable and the main boom element for pivoting the main boom and the structure carried thereby about a horizontal axis and through a range of movement which will generally extend from slightly below the horizontal position to a near vertical position or slightly greater than degrees. The telescopically mounted boom element or slidable boom element, one of which is shown in the drawings, is adapted to be powered or moved through its sliding movement by means of an actuator or hydraulic motor, indicated at 22, as a linear hydraulic motor. Its cylinder is connected to the main boom element and the shaft extremity 24 is connected to the outer end of the boom element 20. A third or internally slidably mounted extensible element or boom element 30 is shown mounted within the boom element and the hydraulic actuator for the same is omitted for simplicity, it being capable of manual or motive extension. A suitable winch structure 40 is indicated as mounted on or carried by the end of the third element or extensible element 30. Similarly, an anger 45 is shown mounted on the end of the extensible element 20 and suspended therefrom, these being typical working elements connected with an articulated scaffold of this type. However, it may be recognized that other types of working elements may be included thereon to be powered by motors controlled from a remote point in such a system.

This articulated scaffold as shown in FIG. 1 includes a personnel supporting platform 50 which is carried by a suitable platform mounting. member or elbow 60, the latter being pivotally mounted on a bracket member 70 slidably carried on the boom element 20 and journaled thereon through bearing means indicated at 74. It includes a rotary hydraulic motor, indicated at 72, connected between the bracket 70 and the elbow 60 for the purpose of rotating the elbow or platform support 60 in a vertical planeand about a horizontal axis. The

- personnel carrying support 50 mounted on the ends of the same is pivotally connected to the end of the elbow through a pivot structure 68 and the elbow member formed of parts 62, 64 in turn is pivoted along its extent, as indicated at 65 to be tilted translationally for the purpose of further orienting the platform with respect to the boom structure for accessibility of the workman to the working area and working tools. A suitable motive means 80 of the hydraulic type is carried by the elbow member and connected respectively between the parts thereof for the purpose of performing the limited tilting or translational movement of the part 64 with respect to the part 62 carried by the slidable bracket 70. The latter is also motor operated in the sense that it is slidably positioned along the extent of the boom element 20 through a motor 75 having a cylinder 76 connected to the bracket and a shaft extremity 77 connected to a flange 78 on the main boom element 16 through a pivot structure 79. Thus, the hydraulic actuator 75 will extend or retract the bracket and hence, the elbow support for the platform along the extent of the boom element 20 and relative to the end of the boom 16 for orientation purposes. Similarly, the boom element 20 will be extended or retracted with respect to the main boom or root boom 16 through operation of the hydraulic actuator 22. The support on the end of the elbow structure 60 will be pivoted translationally with respect to the boom and in the vertical plane of movement by means of the actuator 80.

This mobile aerial tower or articulated scaffold may vary in shape and in the number of parts thereof as well as the particular motive means employed for operating the same. The structure is normally operated from a hydraulic power supply and linear hydraulic actuators and rotary hydraulic actuators are employed to impart the relative movement between the parts as required by the function thereof. The actuators are powered from the hydraulic power source and controlled through control valves, to be hereinafter identified,

which would be incorporated on the base structure 12 or chassis 10 with the fluid power lines directed through pivot points and rotary couplings (not shown) positioned along the extent of the boom element and at the pivot points thereof for the purpose of connecting the source to the respective actuators. As will be hereinafter identified, the specific control valves associated therewith will control not only bidirectional movement of the actuators, where required, but also speed of response of the same through proportional operation of one of the control valves and directional operation of the other control valves to vary the direction and amount or rate offluid flow to the respective actuators.

For purposes of the present disclosure, the remote control aspects of the boom motors are effected between a transmitter, indicated generally at 100, and a receiver, indicated generally at 110, the transmitter being portable and being adapted to be either carried on the workmans platform or by the operator at any point including ground locations. The receiver is fixed to the chassis and is connected through the electrical source (not shown) on the chassis for powering the same with electrical outputs therefrom being directed to control valves, to be hereinafter identified, of the electromagnetic type controlling the hydraulic circuit. In FIG. 2, the transmitter is shown as incorporating a plurality of manual levers each adapted to control bidirectionally the respective motors through operation of the three position switch. The additional lever 107 is indicated as having a plurality of positions to either side of a reference position for a plurality of switching steps to either side of a reference position for proportional control as will be hereinafter identified. The portable transmitter includes a power source or battery 106 connected to a transmitter 107 for powering the same and also to a logic network, indicated generally at 104, as incorporating a plurality of electronic control panel or boards positioned within the transmitter and controlled by the switches. The receiver, which is shown in FIG. 3 in block form, incorporates an electronic receiver structure 112 the output of which is fed into an electronic decoding network formed of a plurality of boards 114. This structure will be powered from the power supply at the chassis and electrical responses therefrom will be directed from the receiver to the electromagnetic control valves, as hereinafter identified. A suitable override control in the form of switches on face of the receiver, as indicated generally at 116, are available for operator operation independent of the transmitter, at the receiver site. The details of the transmitter and receiver form no part of the present invention and the specific logic network and-transmitter and receiver components may be found in the co-pending application of Robert Bonner and John Wiehe, Ser. No. 249,382, filed May 1, 1972 on RADIO CONTROL SYSTEMS FOR MOBILE AERIAL PLATFORMS.

FIG. 4 shows schematically the electric hydraulic circuit for controlling the mode of operation of elements mounted on the scaffolding. It will be understood, however, that the improved electric hydraulic circuit may be employed for control of a plurality of motors irregardless of the application thereof and from a remote point. Similarly, a connectionless or radio type transmission is employed between the sender and receiver or transmitter receiver in the embodiment disclosed. It will be understood further that in its broadest aspects,

the simplified control apparatus at the sending and receiving station may be of the connection type and/or may employ other means of transmission other than radio signals. Thus in FIG. 4, the transmitter 100 with the appropriate control handles 105 and 107 thereon will transmit signals to the receiver 110 having the appropriate logic and decoder apparatus 104 associated therewith. The same will be energized from a power supply on the chassis, indicated at 115, through conduits 116 connected thereto. The power supply 115 will normally be a battery source charged by the motive unit on the truck chassis which will also energize a motor pump combination for the hydraulic source. The hydraulic circuit incorporates the fluid tank 135 or reservoir which is connected to a pump 130, the pump being coupled to a driving source 120 through a mechanical connection 125 for operating the same. The same will be operated continuously when the equipment is in operation and a bypass valve 150 connected in series with the outflow of the pump will control flow of hydraulic fluid to the outlet conduit 151 therefrom. A suitable bypass conduit 152 is connected to the dump valve and under normal operation whenever the dump valve is de-energized, the bypass will-be operative to bypass fluid from the pump back to the reservoir maintaining the hydraulic system de-energized. The flow of hydraulic'fluid from the outlet of the dump valve through the main passage thereof will be directed through a proportional control valve 160 whose outlet will be directed to an outlet conduit 161 feeding through a plurality of conduits 162. A plurality of control valves 163 170 are connected in series circuit with the conduits 162. The outlets of the control valves 163 170, which are of the four way type, are directed to return conduits 172 leading back to the reservoir. The receiver output is directed through a cabling'indicated at 185 to feed the electrical or electromagnetic control, as indicated at 186, of a dump valve 150, which is of the three way type and the electromagnetic input coils of the respective control valves 163 170 for selective operation of the same. In addition, it feeds the control coil of the proportional valve 160 which proportionally valves the control of fluid to all of the directional valves 1'63 '170 which are located in series relationship therewith. The respective valves 163 170 are connected in controlling relationship with the actuators 75, 80, 45, 18, 23, 13, 72 and 40, as previously identified as the various mode of elements on the mobile scaffolding including the working or powering units for the winch and auger carried thereby as working tools. Irrespective of whether the actuators are linear, that is bidirectional or rotary, the four way valves will direct flow into the respective actuators from the main supply conduit leading from the proportional valve 160 with the return being connected to the return conduits 172 leading back to the reservoir 135. In this embodiment of the invention, the control handle 107 will control the operation of the control proportional valve 160 which will proportionately direct flow from the hydraulic source or tank pump combination to the line in which one or more of the directional valves 163 170 may be operated simultaneously. The proportional valve will control the speed or rate of tlow of hydraulic fluid from the pump to the respective actuators so energized by operation of the respective control valves so that they will operate simultaneously at the same speed. Under thev normal sequence of operation,

only one controller will be operated at a time in which case the proportional valve will be in direct control of the same and direction of the same will be controlled by the operation of the directional valve directly associated therewith. However, when two or more functions are desired to be operated simultaneously, the single proportional control valve will eifect proportional flow to each of the same controlling the speed of operation with the direction of operation being controlled by the respective directional control valves.

The improved electro-hydraulic control system permits simplification of the hydraulic circuit'in requiring only one relatively expensive proportional control valve with a plurality of two position or bidirectional control valves at each of the actuator locations. Similarly, the control apparatus for energizing the same at the receiver location and the associated logic apparatus at the receiver and transmitter locations is thereby simplified. For example, in the radio control type apparatus, only one channel of the transmitter need employ logic circuits necessary to provide the various proportional stepped signals for the respective channel while the remaining channels can be of the on-off type or bidirectional control. As in the Bonner and Wiehe copending application previously identified, this logic network will provide for binary type signals which in its simplified form for the directional controls need be only two different signals, thereby simplifying the logic, the synchronizing and the conversion circuit for all except the proportional control channel. A similar saving in the electronics is found in the receiver location where the radio signals which have been converted from parallel to serial form for transmission purposes are received and decoded and reconve rted to a parallel form for simultaneous operation of more than one actuator along with a proportional control valve. Thus, a significant savings in the electronics of a radio remote control transmission system is effected in addition to the simplified hydraulics as previously described. This same savings is effected with the connection type of remote control system in that the transmitter location and receiver location will require only appropriate controllers of a more simplified form for all but the proportional control channel.

Therefore in considering thisinvention it should be remembered that the present disclosure is intended to be illustrative only and the scope of the invention should be determined by the appended claims.

What is claimed is:

1. A remote control circuit comprising, a remote transmitter having controls thereon to provide directional control signals for a plurality of functions and one control for providing control signals for proportional control selectively of one or more of the functions, a receiver coupled to the transmitter and adapted to respond to control signals therefrom, a hydraulic power circuit connected to said receiver and controlled thereby, a plurality of hydraulic motors connected to means adapted to perform the plurality of functions, a hydraulic source and pump providing a source of hydraulic fluid under pressure for the hydraulic circuit and included therein, a plurality of control valves connected respectively to each of said motors and connected in a parallel relationship to one another and in a series circuit with the hydraulic supply, a proportional control valve positioned in series relationship with the hydraulic supply and with the plurality of control valves in parallel relationship, said receiver having a plurality of channels connectedrespectively to the control valves to respond to the directional control signals and a separate control channel responsive to the proportional control signals of the transmitter and connected to the proportional control valve to proportionally control flow of hydraulic fluid from said hydraulic source to said motors with selective operation of the motors in accord with the control valves.

' 2. A mobile aerial tower comprising, a mobile platform, an articulated boom mounted on the platform, hydraulic motor means connected to parts of said boom for orienting the same in at least two axes of movement, an additional boom element including a personnel carrying basket at the extremity of the same connected to the boom, additional hydraulic motor means for orienting said additional boom element and said basket thereon with respect to the articulated boom about at least one axis of movement, a hydraulic pressure source for operating said hydraulic motors positioned on the mobile platform and connected respectively to each of said hydraulic motors, control valve means positioned in the connection between the source and each of said motors for operating said hydraulic motors, transmitter means including a plurality of controllers for providing signals for controlling said hydraulic motors, receiver means mounted on the platform and including means responsive to signals from the transmitter to energize the control valve means of each of said hydraulic motors to provide for operation of the hydraulic motor in accord with selective controller position, additional controller means positioned in the transmitter and having a plurality of positions to either side of a reference position to provide variable signals for variable speed control of said motors, means including in said receiver and responsive to the variable signals from said transmitter in accord with the additional controller position and a proportional valve means positioned between the hydraulic pressure source and each of said control valve means to proportion hydraulic flow from the source to each of said control valve means to effect variable speed operation selectively of said hydraulic motors being controlled by said control valve means.

3. The mobile aerial tower of claim 2 in which the control valve means are on-off valves.

4. The mobile aerial tower of claim 2 in which the control valve means are three position valves having a center off position and reversible flow positions to either side of the center off valve position to bidirectionally control flow to the hydraulic motors for reversible operation of the same.

5. The mobile aerial tower of claim 2 and including manual override means for each of the hydraulic motors and connected to the respective control valve means for the hydraulic motors to override the energization of the control valve means from the receiver and operate the motors independent of the transmitter.

6. The mobile aerial tower of claim 2 and including bypass valve means positioned in the connection between the hydraulic source and the proportional valve means and adapted to bypass flow of hydraulic fluid from the source to said motors.

7. The mobile aerial tower of claim 6 in which the bypass valve means is operatively connected to the hydraulic source and said receiver to become operative with operation of the receiver to connect the hydraulic source of fluid to the motors through the proportional and control valves.

8. The mobile aerial tower of claim 7 and including additional means in the manual override means of the receiver for operating the bypass valve to connect the source of hydraulic fluid to said motors through the proportional valve and control valves independent of the operation of the receiver and with operation of the manual override means.

9. The mobile aerial tower of claim 2 and including additional controller means in the transmitter and operative to transmit control signals to said receiver with said receiver including additional means responsive thereto, work performing devices mounted on the articulated boom and including separate motormeans connected to the hydraulic source and control valve means associated therewith operative to control the operation of said additional motor means, said additional motor means and control valve means being connected in the hydraulic circuit with the proportional valve to provide for proportional energization of the additional motor means with operation of said respective control valve means.

10. The remote control circuit of claim 1 in which the control valves are on-off valves to selectively provide energization and de-energization of the hydraulic motors from the hydraulic source.

1 l. The remote control circuit of claim 1 in which the hydraulic motors are reversible and the control valves are three positional valves effecting directional flow from said hydraulic source to said hydraulic motors to reversibly control the operation of the same.

12. The remote control circuit of claim 1 in which the remote transmitter includes a plurality of channels each associated with one of the controls for the respective plurality of functions and adapted to transmit onoff logic signals in series form from the transistor and with the proportional control adapting to transmit proportional control signals from a proportional control channel, said receiver including a corresponding plurality of channels adapted to receive the on-off logic signal and the proportional logic signals in serial form and transmitted to the control valves and the proportional valve simultaneously for simultaneous operation selectively of the control valves and the proportional valve depending upon the signals transmitted from the transmitter. 

1. A remote control circuit comprising, a remote transmitter having controls thereon to provide directional control signals for a plurality of functions and one control for providing control signals for proportional control selectively of one or more of the functions, a receiver coupled to the transmitter and adapted to respond to control signals therefrom, a hydraulic power circuit connected to said receiver and controlled thereby, a plurality of hydraulic motors connected to means adapted to perform the plurality of functions, a hydraulic source and pump providing a source of hydraulic fluid under pressure for the hydraulic circuit and included therein, a plurality of control valves connected respectively to each of said motors and connected in a parallel relationship to one another and in a series circuit with the hydraulic supply, a proportional control valve positioned in series relationship with the hydraulic supply and with the plurality of control valves in parallel relationship, said receiver having a plurality of channels connected respectively to the control valves to respond to the directional control signals and a separate control channel responsive to the proportional control signals of the transmitter and connected to the proportional control valve to proportionally control flow of hydraulic fluid from said hydraulic source to said motors with selective operation of the motors in accord with the control valves.
 2. A mobile aerial tower comprising, a mobile platform, an articulated boom mounted on the platform, hydraulic motor means connected to parts of said boom for orienting the same in at least two axes of movement, an additional boom element including a personnel carrying basket at the extremity of the same connected to the boom, additional hydraulic motor means for orienting said additional boom element and said basket thereon with respect to the articulated boom about at least one axis of movement, a hydraulic pressure source for operating said hydraulic motors positioned on the mobile platform and connected respectively to each of said hydraulic motors, control valve means positioned in the connection between the source and each of said motors for operating said hydraulic motors, transmitter means including a plurality of controllers for providing signals for controlling said hydraulic motors, receiver means mounted on the platform and including means responsive to signals from the transmitter to energize the control valve means of each of said hydraulic motors to provide for operation of the hydraulic motor in accord with Selective controller position, additional controller means positioned in the transmitter and having a plurality of positions to either side of a reference position to provide variable signals for variable speed control of said motors, means including in said receiver and responsive to the variable signals from said transmitter in accord with the additional controller position and a proportional valve means positioned between the hydraulic pressure source and each of said control valve means to proportion hydraulic flow from the source to each of said control valve means to effect variable speed operation selectively of said hydraulic motors being controlled by said control valve means.
 3. The mobile aerial tower of claim 2 in which the control valve means are on-off valves.
 4. The mobile aerial tower of claim 2 in which the control valve means are three position valves having a center off position and reversible flow positions to either side of the center off valve position to bidirectionally control flow to the hydraulic motors for reversible operation of the same.
 5. The mobile aerial tower of claim 2 and including manual override means for each of the hydraulic motors and connected to the respective control valve means for the hydraulic motors to override the energization of the control valve means from the receiver and operate the motors independent of the transmitter.
 6. The mobile aerial tower of claim 2 and including bypass valve means positioned in the connection between the hydraulic source and the proportional valve means and adapted to bypass flow of hydraulic fluid from the source to said motors.
 7. The mobile aerial tower of claim 6 in which the bypass valve means is operatively connected to the hydraulic source and said receiver to become operative with operation of the receiver to connect the hydraulic source of fluid to the motors through the proportional and control valves.
 8. The mobile aerial tower of claim 7 and including additional means in the manual override means of the receiver for operating the bypass valve to connect the source of hydraulic fluid to said motors through the proportional valve and control valves independent of the operation of the receiver and with operation of the manual override means.
 9. The mobile aerial tower of claim 2 and including additional controller means in the transmitter and operative to transmit control signals to said receiver with said receiver including additional means responsive thereto, work performing devices mounted on the articulated boom and including separate motor means connected to the hydraulic source and control valve means associated therewith operative to control the operation of said additional motor means, said additional motor means and control valve means being connected in the hydraulic circuit with the proportional valve to provide for proportional energization of the additional motor means with operation of said respective control valve means.
 10. The remote control circuit of claim 1 in which the control valves are on-off valves to selectively provide energization and de-energization of the hydraulic motors from the hydraulic source.
 11. The remote control circuit of claim 1 in which the hydraulic motors are reversible and the control valves are three positional valves effecting directional flow from said hydraulic source to said hydraulic motors to reversibly control the operation of the same.
 12. The remote control circuit of claim 1 in which the remote transmitter includes a plurality of channels each associated with one of the controls for the respective plurality of functions and adapted to transmit on-off logic signals in series form from the transistor and with the proportional control adapting to transmit proportional control signals from a proportional control channel, said receiver including a corresponding plurality of channels adapted to receive the on-off logic signal and the proportional logic signals in serial form and transmitted to the control valvEs and the proportional valve simultaneously for simultaneous operation selectively of the control valves and the proportional valve depending upon the signals transmitted from the transmitter. 